血清同型半胱氨酸及超敏C反应蛋白水平与老年原发性高血压患者颈动脉粥样硬化程度的关系研究

目的:探讨血清同型半胱氨酸(Hcy)及超敏C反应蛋白(hs-CRP)水平与老年原发性高血压患者颈动脉粥样硬化程度的关系。方法:选择我院于2015年5月至2017年10月收治的141例老年原发性高血压患者作为研究对象。检测所有患者颈动脉内膜-中层厚度(IMT),并根据IMT将其分为正常组(IMT≤1.0 mm,n=28)、增厚组(1.0 mmIMT1.5 mm,n=53)和斑块组(IMT≥1.5 mm,n=60)。比较三组患者血清Hcy、hs-CRP、总胆固醇(TC)及低密度脂蛋白胆固醇(LDL-C)水平,采用Pearson相关分析四项指标与IMT的相关性,采用多元线性逐步回归分析IMT增厚的影响因素。结果:增厚组与斑块组血清Hcy、hs-CRP、TC、LDL-C水平均明显高于正常组,且斑块组血清Hcy、hs-CRP、TC、LDL-C水平明显高于增厚组,差异具有统计学意义(均P0.05)。Pearson相关分析结果表明,血清Hcy、hs-CRP、TC、LDL-C水平均与IMT呈正相关关系(r=0.775、0.836、0.492、0.415,均P0.05)。多元线性逐步回归分析结果显示,血清Hcy、hs-CRP均为IMT增厚的独立危险因素(OR=5.689、7.381,均P0.05)。结论:老年原发性高血压患者颈动脉粥样硬化程度与血清Hcy、hs-CRP关系密切,临床上检测其Hcy、hs-CRP水平可在一定程度上评估颈动脉粥样硬化程度。     

急性脑梗死患者颈动脉斑块内新生血管超声造影评价及其与血脂指标和超敏C反应蛋白水平的关系研究

目的:探讨急性脑梗死患者颈动脉斑块内新生血管超声造影评价及其与血脂指标和超敏C反应蛋白水平的关系。方法:选取2018年6月到2019年6月期间我院收治的ACI患者186例,根据患者的颈动脉内中膜厚度(IMT)数值以及颈动脉斑块内新生血管超声造影情况将其分为无斑块组、稳定斑块组和易损斑块组。对比各组患者的总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)、三酰甘油(TG)、高密度脂蛋白胆固醇(HDL-C)、美国国立卫生研究院卒中量表(NIHSS)评分、改良的Rankin评分(m RS)、超敏C反应蛋白(hs-CRP)水平。结果:易损斑块组和稳定斑块组患者的TC、LDL-C、TG、hs-CRP水平均明显高于无斑块组(P<0.05),易损斑块组患者的LDL-C、hs-CRP水平均明显高于稳定斑块组(P<0.05),易损斑块组和稳定斑块组患者的NIHSS评分和m RS评分均明显高于无斑块组(P<0.05),易损斑块组患者的NIHSS评分和m RS评分均明显高于稳定斑块组(P<0.05),经Pearson分析显示,LDL-C、hs-CRP、NIHSS评分和m RS评分与斑块分级均呈正相关(P<0.05)。结论:颈动脉斑块内新生血管超声造影技术可有效评估ACI患者的斑块稳定性,ACI患者的斑块分级与脂代谢紊乱、机体的炎症反应以及患者病情严重程度和预后均存在一定的相关性。     

阿托伐他汀治疗高血压并颈动脉粥样硬化的临床疗效观察

目的:观察阿托伐他汀治疗高血压并颈动脉粥样硬化的临床疗效。方法:选择高血压并颈动脉粥样硬化患者64例,按照自愿的原则分为对照组和观察组,对照组给予常规治疗,观察组在常规治疗的基础上给以阿托伐他汀治疗。治疗6个月后,比较两组患者血压、血脂及颈动脉斑块分级情况。结果:治疗6周后,两组患者在上述方面比较,差异均具有统计学意义,观察组优于对照组。结论:在高血压并颈动脉粥样硬化患者药物治疗过程中,应加行阿托伐他汀治疗,可提高临床疗效。     

Structural compliance: A new metric for protein flexibility

Proteins are the active players in performing essential molecular activities throughout biology, and their dynamics has been broadly demonstrated to relate to their mechanisms. The intrinsic fluctuations have often been used to represent their dynamics and then compared to the experimental B-factors. However, proteins do not move in a vacuum and their motions are modulated by solvent that can impose forces on the structure. In this paper, we introduce a new structural concept, which has been called the structural compliance, for the evaluation of the global and local deformability of the protein structure in response to intramolecular and solvent forces. Based on the application of pairwise pulling forces to a protein elastic network, this structural quantity has been computed and sometimes is even found to yield an improved correlation with the experimental B-factors, meaning that it may serve as a better metric for protein flexibility. The inverse of structural compliance, namely the structural stiffness, has also been defined, which shows a clear anticorrelation with the experimental data. Although the present applications are made to proteins, this approach can also be applied to other biomolecular structures such as RNA. This present study considers only elastic network models, but the approach could be applied further to conventional atomic molecular dynamics. Compliance is found to have a slightly better agreement with the experimental B-factors, perhaps reflecting its bias toward the effects of local perturbations, in contrast to mean square fluctuations. The code for calculating protein compliance and stiffness is freely accessible at https://jerniganlab.github.io/Software/PACKMAN/Tutorials/compliance .     

Human leg design: optimal axial alignment under constraints

Alignment of joints with respect to the leg axis reduces the moment arm of external forces and therefore joint torques. Moreover, it affects the gearing of muscle forces and displacements. Thus, it influences tissue stress, cost of support and locomotion, and stability. Assuming that alignment is of general advantage we propose a mathematical criterion quantifying the axial alignment using the static torque equilibrium of a three-segment leg. Using this criterion derived from joint torque minimisation we asked for optimal leg designs (segment lengths and joint angles) at varied leg lengths. The trivial straight is best solution is excluded and the configuration space is restricted by geometrical constraints such as the ground contact. For different total leg lengths we could identify different optimal segment length combinations and appropriately adjusted joint angles. The extended human leg configuration characterised by a short foot and a combination of unequal ankle and knee angles emerges as a global optimum from our analysis. For crouched configurations allowing for larger leg extensions an angle symmetrical 1:1:1 segment length combination is best. The plantigrade optimum is enforced by the requirement of the distal segment (foot) being shorter than the opposite outer segment (thigh), as well as by the ground contact constraint. Different (e.g. digitigrade) geometries might be of advantage in different biological contexts with different constraints. The fact that small mammals use a crouched equal segment design implies that other locomotor requirements such as stability, strain rates, and acceleration distance per step might dominate.Send offprint requests to: M. Günther (Tübingen)     

Blood pressure changes validate phase related external suction, a controlled method for stimulation of human baroreceptors

Phase related external suction (PRES), a new controlled method for manipulating activity in human baroreceptors, applies precisely timed bursts of suction and pressure within the cardiac cycle through an external neck cuff. Seven healthy adult men participated in 32 pseudo-random trials of baroreceptor stimulation and inhibition. Blood pressure was assessed both intra-arterially and with a noninvasive device. In the present study, PRES baroreceptor stimulation elicited invasively measured blood pressure decreases of about 2.5 mmHg (0.33 kPa) and heart rate decreases of about 5 beats · min^–1, while baroreceptor inhibition increased invasively measured blood pressure by about 1.5 mmHg (0.20 kPa) and heart rate about 2.5 beats · min^–1. It was concluded that PRES is an effective method for baroreceptor manipulation with weaker size effect but better control of nonspecific factors in human subjects than other baroreceptor manipulation techniques. The noninvasive blood pressure measurement device was less sensitive to experimental variation than was the invasive device.     

Arteriovenous anastomoses in the cat carotid body

Summary In artery surrounding areas in the periphery of the carotid body of the cat we found arteriovenous anastomoses differing in respect to their character. So far, it is not yet to decide the frequency of their occurrence and their functional significance. The anastomoses were demonstrated by light microscopy of serial sections and by scanning electron microscopy with a more developed corrosion casting technique.

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Zusammenfassung In den arteriennahen, peripheren Bereichen des Glomus caroticum der Katze wurden arteriovenöse Verbindungen nachgewiesen, die ihrem Charakter nach unterschiedlich sind. Es ist allerdings noch nicht zu entscheiden, ob derartige Anastomosen regelmäßig vorkommen und wie sie funktionieren. Die beschriebenen Gefäßverbindungen konnten lichtmikroskopisch anhand von histologischen Serienschnitten und mit Hilfe einer weiterentwickelten Korrosionstechnik im Rasterelektronenmikroskop dargestellt werden.

     

Immunofluorescent and structural features of cells in the intervascular stroma of the amphibian carotid labyrinth

Summary The amphibian carotid labyrinth consists of a pars cavernosa, the main chamber of which is in communication with both the base of the external carotid artery, and the vessels of the labyrinthine pars capillaris. On the walls of the main chamber is a network of thick strands of connective tissue and modified smooth muscle cells surrounding the openings into the p. capillaris. These openings lead into wide-diameter atrial vessels, which in turn branch to form the short narrow-diameter vessels. The short vessels form the major component of the labyrinth. A few extremely narrow-diameter vessels are also present. The short vessels open into the roots of the internal carotid artery on the ventral aspect of the carotid labyrinth. The intervascular stroma of the p. capillaris contains numerous stellate and bipolar cells. These cells give a positive response to an immunofluorescent technique specific for smooth muscle myosin and tropomyosin. As the ultrastructural features of these cells are comparable in many respects to smooth muscle, they have been designated as modified smooth muscle cells. It is proposed that these cells act in both an active and passive fashion in maintaining the luminal dimensions of the short vessels relatively constant.     

iPSC‐derived human mesenchymal stem cells improve myocardial strain of infarcted myocardium

We investigated global and regional effects of myocardial transplantation of human induced pluripotent stem cell (iPSC)‐derived mesenchymal stem cells (iMSCs) in infarcted myocardium. Acute myocardial infarction (MI) was induced by ligation of left coronary artery of severe combined immunodeficient mice before 2 × 10⁵ iMSCs or cell‐free saline were injected into peri‐infarcted anterior free wall. Sham‐operated animals received no injection. Global and regional myocardial function was assessed serially at 1‐week and 8‐week by segmental strain analysis by using two dimensional (2D) speckle tracking echocardiography. Early myocardial remodelling was observed at 1‐week and persisted to 8‐week with global contractility of ejection fraction and fractional area change in saline‐ (32.96 ± 14.23%; 21.50 ± 10.07%) and iMSC‐injected (32.95 ± 10.31%; 21.00 ± 7.11%) groups significantly depressed as compared to sham control (51.17 ± 11.69%, P < 0.05; 34.86 ± 9.82%, P < 0.05). However, myocardial dilatation was observed in saline‐injected animals (4.40 ± 0.62 mm, P < 0.05), but not iMSCs (4.29 ± 0.57 mm), when compared to sham control (3.74 ± 0.32 mm). Furthermore, strain analysis showed significant improved basal anterior wall strain (28.86 ± 8.16%, P < 0.05) in the iMSC group, but not saline‐injected (15.81 ± 13.92%), when compared to sham control (22.18 ± 4.13%). This was corroborated by multi‐segments deterioration of radial strain only in saline‐injected (21.50 ± 5.31%, P < 0.05), but not iMSC (25.67 ± 12.53%), when compared to sham control (34.88 ± 5.77%). Improvements of the myocardial strain coincided with the presence of interconnecting telocytes in interstitial space of the infarcted anterior segment of the heart. Our results show that localized injection of iMSCs alleviates ventricular remodelling, sustains global and regional myocardial strain by paracrine‐driven effect on neoangiogenesis and myocardial deformation/compliance via parenchymal and interstitial cell interactions in the infarcted myocardium.     

Sequence-Dependent Stability of Intramolecular DNA Triple Helices

Abstract

A set of 21 oligodeoxynucleotides were designed to fold into intramolecular triple helices of the pyrimidine motif under appropriate conditions. UV melting experiments on the triplexes which only differ in the number and distribution of third strand cytosines reveal the influence of sequence and pH on triplex stability and can be summarized as follows: (1) increasing the cytosine content in the third strand results in a higher thermal stability of the triplex at acidic pH but lowers the triplex to duplex melting temperature at neutral pH; (2) cytosines at terminal positions destabilize the triple helical structure as compared to non-terminal positions; (3) contiguous cytosines lead to a pH dependent destabilization of the triplex, the destabilizing effect being more pronounced at higher pH. Analysis of these effects in terms of the various interactions within a triple helical complex indicate that the sequence-dependent stabilities are largely determined by the extent of protonation for individual third strand cytosines.